The present invention, in some embodiments thereof, relates to a materials dispenser and, more particularly, but not exclusively, to devices for dispensing liquids, pastes, foams, and the like, under pressure.
Aerosol spray cans are known throughout modern society, and are used in a myriad of products found in food stores, pharmacies, tool shops, and more. Fire extinguishers also provide a stream of material under pressure.
Aerosol canisters typically deliver material pressurized to seven or eight bars. A few methods are popular. Single Compartment methods mix a deliverable material with a propellant (a pressurized gas), and spray both through a valve. Dual Compartment methods separate the deliverable material from the propellant to avoid interaction between them, to increase shelf life of the product, and for various other reasons. Some Dual Compartment methods use a bag for deliverable material. Some separate material from propellant using a piston barrier. In both cases a compartment with a compressed propellant is used to pressurize a compartment with a deliverable material, which can then be delivered under pressure through a valve. Practical considerations, and in some jurisdictions also laws and regulations require that containers for aerosol products using a propellant (typically pressurized to 7-8 bars) to be cylindrical in format, for safety reasons. Containers are also required to be metal or of thick glass or of rigid plastic, or in any case to be of sufficient strength and thickness to safely withstand this pressure. If made of metal other than aluminum (which is relatively expensive), containers are usually made out of TinPlate and coated with lacquers or other coatings to prevent them from rusting and releasing the pressure in unintended ways. As a result, aerosol containers are often relatively expensive to make, to transport, and to handle in bulk, are restricted to a standard shape, and are difficult to dispose of in an ecologically desirable manner.
For low pressure dispensing applications, the state of the art is generally that users use manual pressure to pump or squeeze products from containers, for example to get food and suntan lotion out of plastic squeeze bottles, or to get toothpaste and pharmaceuticals out of collapsible tubes, or press on a mechanical pump to deliver the product. In addition to the potential inconvenience attached to the use of many such packages, they suffer from the additional potential disadvantage that air entering such packages interacts with the material therein, reducing shelf life. An additional possible disadvantage is that it is often difficult or impossible to empty them completely, leading to either a messy operation or wastage of products, frustration of users, and/or unnecessary expense.
Additional background art includes U.S. Pat. No. 4,121,737, International Patent Application Publication No. WO9509784, U.S. Pat. No. 4,222,499, DE102004028734, U.S. Pat. No. 5,127,554, International Patent Application Publication No. WO2004080841, U.S. Pat. No. 2,966,282, GB2209056, International Patent Application Publication No. WO0115583, U.S. Pat. No. 3,981,415, EP0248755, FR2608137, U.S. Patent Application No. US2009045222, U.S. Patent Application No. US2006243741, GB2278823, U.S. Pat. No. 4,077,543, FR2707264(A1), U.S. Pat. Nos. 3,791,557, 5,111,971, 4,251,032, 5,927,551, 4,964,540, 5,060,700, 4,981,238, International Patent Application Publication No. WO/2010/145677, International Patent Application Publication No. WO/2010/085979.